In general, a balloon catheter and a stent are medical tools surgically installed within a lumen or blood vessel and configured to expand the lumen or blood vessel when a disease is generated, such as when the unique function of a lumen within the human body is reduced due to the lumen narrowed by various types of diseases generated within the human body or when the circulation of the blood becomes poor due to a narrowed blood vessel.
A coronary artery disease or an ischemic heart disease is a disease generated because fat-forming elements are deposited on the wall of a coronary artery blood vessel, the lumen of the coronary artery is gradually narrowed as an inflammatory response accompanied by the deposition, and the blood is not sufficiently supplied to the heart muscle due to the narrowed lumen size of the coronary artery.
If the blood is not sufficiently supplied to the heart muscle, a pain in the chest, a difficulty in breathing, and other symptoms are generated depending on a degree thereof. Such a coronary artery disease appears as a clinical sign, such as angina, acute myocardial infarction, or a sudden heart failure.
Percutaneous Coronary Intervention (PCI) is a treatment method of physically expanding the lumen of the coronary artery that has been narrowed because cholesterol is deposited on a blood vessel wall using a balloon catheter or a stent.
FIG. 1 is a side view showing a conventional balloon catheter. Referring to FIG. 1, a balloon 2 is provided at the front end of the shaft 1 of the conventional balloon catheter. The balloon 2 may be attached to the front end of the shaft 1 using adhesives, etc.
Meanwhile, a wire discharge hole 3 through which a guide wire is discharged is formed on one side of the shaft 1. As described above, in the existing balloon catheter, the cross section of the shaft 1 in which the wire discharge hole 3 is formed is described below. As shown in FIG. 1, a guide wire lumen 4 through which a guide wire passes and an expansion lumen 5 are together formed within the shaft 1.
That is, the guide wire is inserted into the front end (opened) of the balloon catheter and discharged to the wire discharge hole 3 after passing through the guide wire lumen 4 so that the balloon catheter enters and exits along the guide wire. Liquid (i.e., a solution for the transfer of pressure, for example, a contrast medium and a mixture of saline) for expanding the balloon 2 is supplied to the expansion lumen 5. The liquid for expansion is supplied through a connection port 6 provided at the rear end of the shaft 1. The connection port 6 is a port connected to an expansion-contraction device.
However, the aforementioned prior art has the following problems.
The conventional balloon catheter is problematic in that the diameter of the shaft 1 is generally increased because the guide wire lumen 4 and the expansion lumen 5 are overlapped with each other and formed in the shaft 1. If the diameter of the shaft 1 is increased as described above, pushability is lowered when a surgical operator performs a surgical procedure on the catheter, making the surgical procedure difficult. In particular, there is a problem in that a surgical procedure for a tortuous blood vessel, such as the heart blood vessel, is difficult.
Furthermore, if the guide wire lumen 4 and the expansion lumen 5 are formed together, there is a problem in that the time taken to expand and contract the balloon 2 becomes long because the diameter of the expansion lumen 5 is inevitably relatively reduced.